TROJ_FAKEAV.ZZS

 Analysis by: Sabrina Lei Sioting

 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan may be downloaded from remote sites by other malware.

It displays fake alerts. It displays fake alerts that warn users of infection. It also displays fake scanning results of the affected system. It then asks for users to purchase it once scanning is completed. If users decide to purchase the rogue product, users are directed to a certain website asking for sensitive information, such as credit card numbers.

  TECHNICAL DETAILS

File Size:

1,174,528 bytes

File Type:

PE

Memory Resident:

No

Initial Samples Received Date:

31 Jul 2010

Payload:

Connects to URLs/Ips, displays fake alerts

Arrival Details

This Trojan may be downloaded from remote site(s) by the following malware:

  • TROJ_WALEDAC.AIR

Installation

This Trojan drops the following copies of itself into the affected system:

  • %Application Data%/{random numbers}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It adds the following possibly malicious files or file components:

  • %User Profile%\Start Menu\Programs\Security Tool.lnk

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{random numbers} = %Application Data%\\{random numbers}.exe

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.249.2/cb_soft.php?q=4cb7a9db823c23c5343d4c222c187c1b

Rogue Antivirus Routine

This Trojan displays fake alerts.

It displays fake alerts that warn users of infection. It also displays fake scanning results of the affected system. It then asks for users to purchase it once scanning is completed. If users decide to purchase the rogue product, users are directed to a certain website asking for sensitive information, such as credit card numbers.

  SOLUTION

Minimum Scan Engine:

8.900

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove malware files dropped/downloaded by TROJ_FAKEAV.ZZS

    • TROJ_WALEDAC.AIR

Step 3

Delete the registry entry with an unknown data value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\RunOnce
    • {random numbers}=%Application Data%\\\\{random numbers}.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.ZZS. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


Did this description help? Tell us how we did.